Add new parameter for SIGv4 auth.

[Yury-Fridlyand]

Description

Add new optional parameter for use with AWS_SIGv4 authentication to connect to a cluster via SSH tunnel (for example - OpenSearch cluster is a VPC endpoint). This parameter is required to fix request header to comply SIGv4 requirements. Ref: link.

New UI config parameter + new connection string parameter:

TODOs

• [x] Update docs
• [x] Test on Windows
• [x] Test on Mac
• [x] Test compatibility with older version
• [x] Update logging
• [x] Fix UI to show second word and/or rename
• [ ] Fix UI to auto-activate new field when SIGv4 auth type is chosen
• [x] Trim string prefix and postfix
• [x] Add fix for #39

Issues Resolved

Fixes #41, #39

Check List

• [ ] New functionality includes testing.
  • [ ] All tests pass, including unit test, integration test and doctest
• [ ] New functionality has been documented.
  • [ ] New functionality has javadoc added
  • [ ] New functionality has user manual doc added
• [x] Commits are signed per the DCO using --signoff

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[acarbonetto]

Make sure to update documentation for connections and mention how to connect basic/sigv4 through a tunnel (and what to set as the tunnel host): https://github.com/opensearch-project/sql-odbc/blob/main/docs/user/configuration_options.md